Observational evidence of the association membership of the 19.7-day Cepheid RU Scuti is presented. Photoelectric observations of 20 luminous stars in the vicinity of RU Scuti were obtained with a single-channel, pulse-counting photometer equipped with standard UBV filters, and spectroscopic observations were made in order to derive MK spectral types for 14 of the stars. Two distinct groupings of stars are distinguished: a nearby group associated in terms of distance, reddening and age with the cluster Trumpler 35, and a distant group consisting of stars of larger reddening and younger evolutionary status. Based on an apparent agreement in reddening and evolutionary status, RU Scuti is assigned to the Trumpler 35 association, which would imply an intensity-mean absolute magnitude of -5.19 + or - 0.13 m.e. The presence of two Wolf-Rayet stars in the background association is also noted.